At the production of particleboards the amount of glue used for binding the particles is kept fairly low for economic reasons and around 10 percent based on the dry weight of the particles. This small amount of glue means that the quality of the produced boards and particularly their strength will be sensitive to variations in the production process and dependent also on minor changes of the operation conditions and in the raw-material composition. Particular problems concerning the strength arise when the production process includes steps for reducing the formaldehyde emission from the boards. It is well known that the curable formaldehyde based glue systems, and especially the urea-formaldehyde resins, which are used for the production of particleboards cause release of formaldehyde to some extent both at the production and the use of the boards. Several solutions for avoiding the hygienic problems associated with this emission of free formaldehyde have been suggested and those which are most generally applicable comprise addition of a formaldehyde absorbing agent to the particle material at the production of the boards. A process of this kind is known from DE-A-No. 1 055 806. However, since both the formaldehyde absorbing substance and the resin components of the resin glue are reactive against the formaldehyde problems will occur in these processes and there will be a decrease in strength due to the influence on the glue and an inactivation of the formaldehyde absorbent. Different methods of keeping the absorbing agent separated from the glue have consequently been suggested. The DE-A-No. 1 653 167 and DE-A-No. 2 553 459 suggest that only a part of the amount of particles, or other material is treated with the formaldehyde absorbing agent and then mixed with the main part of the particles to get a separation between the absorbent and the glue. However, the separation is poor in these methods, and, further, the uneven distribution of the absorbent leads to an unsatisfactory absorption. The additional phases also give rise to several economic and practical problems. A simplified method for adding the absorbent is suggested in the DE-A-2 740 207 and here a combined liquid for wax and absorbent is used but the separation of the absorbent and the glue is not improved by this method. According to the SE-C-No. 409 090 separation of the formaldehyde absorbing agent from the glue can be achieved by adding the absorbing agent in the form of a solution to particles having sufficiently low moisture content so that the solution will penetrate into the particles and so that there will not be any essential admixing with the glue which is added subsequently. However, for practical reasons it is not always possible to treat the dry particles and if a drying after the addition is desirable this will carry the absorbent back towards the surface of the particles.